Some image forming apparatus form an image with toner. A developing unit supplies toner to an image bearing member (photosensitive drum) on which an electrostatic latent image is formed, and the electrostatic latent image is developed with toner. A replaceable container (toner container, toner cartridge, etc.) for supplying replenishing toner is mounted to the image forming apparatus. When the toner in the container is used up, the container is replaced by a new one.
There is known an image forming apparatus which does not suspend a job (printing) even when a container is removed. Specifically, there is known an image forming apparatus which includes a photosensitive member for bearing an electrostatic latent image, a forming unit for forming an electrostatic latent image on the photosensitive member, a developing unit for developing the electrostatic latent image borne on the photosensitive member, a container (toner cartridge) that contains toner to be supplied to the developing unit, supplies the toner to the developing unit, and is removably mountable on an image forming apparatus main body, and a detecting unit for detecting the removal/mounting of the container. The image forming apparatus continues a print job when the detecting unit determines that the container has been removed during the print job and prompts a user to mount a container. With this configuration, the print job is not suspended even when the container is removed during the print job, and a user is prompted to mount a container.
The container may be provided with a storage element (for example, an IC tag) for storing various pieces of information. As information to be provided to the container, the storage element may store a toner replenishment amount accumulated after the container is mounted. For example, the accumulated toner replenishment amount is used for grasping a toner residual amount in the container.
Further, the image forming apparatus may be provided with an intermediate hopper that is replenished with toner from the container and supplies the toner to the developing unit. In general, the intermediate hopper stores a larger amount of toner than that stored in the developing unit. Due to the presence of the intermediate hopper, even when the toner in the container is used up, a certain number of sheets can be printed. When the amount of the toner in the intermediate hopper becomes smaller, the intermediate hopper is replenished with toner from the container.
When printing is performed through use of toner in the intermediate hopper in a state in which the intermediate hopper is not replenished with new toner during a period from a time when the container becomes empty (no toner remains in the container) to a time when the container is replaced by a new one, the toner in the intermediate hopper decreases in amount. When the container is replaced by a new one, in order to restore the toner amounts in the intermediate hopper and the developing unit, which have decreased due to the consumption of toner while the container is empty, to prescribed amounts, it is necessary to replenish the intermediate hopper and the developing unit with toner from a new container even when printing is not performed.
Therefore, even when printing is not performed at all, a part of toner may be replenished from the new container merely by replacing the old one by the new one. However, conventionally, there is a problem in that a toner replenishment amount is stored in an IC tag or the like along with the execution of a print job, and hence the toner amount consumed during a period from a time when the container becomes empty to a time when the container is replaced by the new one (the amount of toner to be supplied from a new container to the intermediate hopper merely by replacing the old one by the new one) is not counted as a toner replenishment amount. Therefore, when a toner residual amount is displayed through use of an accumulated toner replenishment amount stored in an IC tag or the like, there is also a problem in that a toner residual amount cannot be displayed precisely due to a difference from the actual residual amount of toner in the container.
In the conventional image forming apparatus, a storage element of a new container does not store a toner amount consumed while the old container is empty. Therefore, the above-mentioned problem cannot be solved. Further, as described above, some conventional image forming apparatus can perform printing even when a container is removed. However, a toner replenishment amount cannot be stored in a storage element during the removal of the container, and hence, the toner amount consumed during the removal of the container is not stored in the storage element. Therefore, there is a problem in that a difference is caused between the accumulated toner replenishment amount stored in the storage element and the amount of toner actually replenished.